TWI517929B - Solder paste - Google Patents

Description

Solder paste

The present invention relates to a solder paste.

In the past, various solder pastes have been used in order to connect electronic circuit parts and the like with solder. In particular, the flux contained in the solder paste can be used as a material for removing the metal oxide on the surface of the solder and the surface of the circuit substrate and preventing reoxidation of the metal during soldering. Moreover, the flux also has an important function of lowering the surface tension of the solder and enabling the smooth execution of the solder.

However, it has been added to a solder paste flux (hereinafter, simply referred to as a flux) by a combination of an organic acid or the like in order to achieve improvement in reliability and weldability. However, in recent years, fluxes that can satisfactorily meet the market demand for heating collapse resistance that has begun to attract attention due to the miniaturization of electronic circuit components and the like have not yet been realized. Fluxes with low heat and collapse resistance sometimes cause solder balls at the wafer parts. Therefore, if the solder ball is detached, the solder ball will fall between the component wires after the gap is narrowed due to the miniaturization of the components, so that the possibility of short-circuit failure increases. Furthermore, the aforementioned market requirements can be said to be quite severe especially for the automotive electronic parts.

In view of the aforementioned heat-resistant collapse resistance, in other words, there have been several proposals for improving the "collapse" caused by heating. For example, specifically, the following various means are mentioned.

(a) A means for adding a polyethylene glycol polypropylene glycol-polyethylene glycol block polymer to a solder paste composition containing a solder powder, a rosin-based resin, an active agent, and a solvent (refer to Patent Document 1).

(b) A means for adding a fluorine compound such as a fluorine-based resin compound or a fluorine-based surfactant to 0.05 to 10% by weight of the flux of the solder paste (refer to Patent Document 2).

(c) In the solder paste in which the solder powder and the paste flux composed of the spherical spherical powder and the amorphous powder of various shapes are mixed, 10 to 50% by weight (relative to the entire solder powder) is mixed. Means for shaping the powder (refer to Patent Document 3).

Patent Document 1: Japanese Laid-Open Patent Publication No. 2002-336993.

Patent Document 2: Japanese Laid-Open Patent Publication No. Hei 6-7989.

Patent Document 3: Japanese Laid-Open Patent Publication No. Hei 7-88675.

Patent Document 4: Japanese Laid-Open Patent Publication No. Hei 9-253884.

As described above, it has been extremely difficult to develop a flux and a solder paste that can be sufficiently applied to an electronic circuit component that is highly refined. For example, even if the means (a) and (b) described in the above Patent Documents 1 and 2 are used, the addition of such a less volatile polar substance remains after the solder is melted, so that sufficient reliability cannot be obtained. Moreover, even if the means (c) described in the above-mentioned Patent Document 3 is used, the addition of the powder having a specific shape not only causes a decrease in the fluidity of the solder paste, but also causes a decrease in the print transfer property of the fine portion.

Further, in the flux in the solder paste composition used in the past, an organic acid is used as an active agent, and in particular, a dibasic acid having a small molecular weight (for example, a molecular weight of 250 or less) is used based on the activity force. Refer to Patent Document 4). However, in the lead-free solder paste which has been frequently used recently, since a stronger active force than the solder paste using the tin-lead alloy is required, a large amount of the above-mentioned dibasic acid must be used. As a result, during the soldering, the organic acid metal salt produced by the reaction between the dibasic acid and the metal oxide cannot be completely dissolved in the flux residue, and the organic acid metal salt is precipitated onto the substrate in a dot form. This precipitate is likely to dissociate the organic acid due to moisture, which may cause corrosion or insulation deterioration.

Thus, it is considered to reduce the content of the dibasic acid contained in the flux in the solder paste composition or to replace the dibasic acid with a monobasic acid. However, when the above method is carried out, even if the problem of precipitation of, for example, a metal salt can be improved, the activity is lowered. As a result, welding failure is often caused by a decrease in the active force.

The present invention can solve the above-mentioned technical problems, and therefore contributes greatly to the realization and practical use of the solder paste which can be sufficiently applied to electronic circuit parts which have been remarkably improved in recent years. In order to achieve high reliability and good solderability at the same time, in particular, focusing on the flux for solder paste and the active agent contained in the solder paste and the improvement of the functionality of the base resin, the inventors actively proceeded. the study. As a result, it has been found that a solder paste containing an active agent (composed of a plurality of kinds of dibasic acids falling within a specific molecular weight range and one type of monobasic acid) and a specific resin additive can simultaneously achieve high reliability. With excellent weldability, the heat collapse resistance can be improved. Moreover, the inventors have confirmed that the solder paste does not increase the manufacturing cost and does not burden the environment. The present invention has been conceived from the foregoing aspects and the reasons.

A solder paste according to the present invention is characterized in that the flux contains at least one resin additive selected from the group consisting of high density polyethylene and polypropylene, and the flux is 100% by weight as a whole. The resin additive is 4% by weight or more and 12% by weight or less, wherein the active agent has a dibasic acid having a molecular weight of 250 or less, a monobasic acid having a molecular weight of 150 or more and 300 or less, and a molecular weight of 300 or more and 600 or less. a. Further, the solder paste has a viscosity at 80 ° C of 400 Pa ‧ or more.

Since the solder paste has the aforementioned active agent, it can simultaneously achieve high reliability and excellent solderability. Further, since at least one selected from the group consisting of high-density polyethylene and polypropylene contributes to the high viscosity of the solder paste under high temperature (80 ° C) conditions, heat-resistant collapse can be improved. Sex. In other words, it is possible to suppress "collapse" caused by heating.

One of the solder pastes of the present invention can improve the resistance to heat collapse. In other words, it is possible to suppress "collapse" caused by heating.

Next, embodiments of the present invention will be described.

As described above, the solder paste flux of the present embodiment has an active agent, and the active agent has a dibasic acid having a molecular weight of 250 or less, a monobasic acid having a molecular weight of 150 or more and 300 or less, and a binary having a molecular weight of 300 or more and 600 or less. acid. Further, the flux for solder paste of the present embodiment also includes at least one resin additive selected from the group consisting of high-density polyethylene and polypropylene, and when the flux is 100% by weight as a whole, the aforementioned The amount of the resin additive added is 4% by weight or more and 12% by weight or less. Further, the solder paste of the present embodiment has a viscosity at 80 ° C of 400 Pa ‧ or more. Further, the high-density polyethylene in the present invention has a density of 942 kg/m ³ or more as described in JIS K6922-1:1997. Similarly, the density of the medium density polyethylene is 930 kg/m ³ or more and less than 942 kg/m ³ ; and the density of the low density polyethylene is 910 kg/m ³ or more and less than 930 kg/m ³ .

Here, the active agent can improve the heat collapse resistance, in other words, the "collapse" caused by the heating can be suppressed. Further, as described above, either or both of the high-density polyethylene and the polypropylene can contribute to the increase in viscosity of the flux and the solder paste at 80 ° C, for example, when the flux for the general solder paste starts to soften. Therefore, for example, in a process generally called reflow by welding and melting a solder to bond a substrate electrode and an electronic component, "collapse" due to heating can be suppressed. In this way, since the solder paste can suppress the occurrence of the solder ball, it can be applied to an electronic circuit component having a remarkable progress in miniaturization.

Further, as the dibasic acid having a molecular weight of 250 or less, a dibasic acid having a molecular weight of 90 or more is preferred. Further, representative examples of the dibasic acid having a molecular weight of 250 or less may be made up of malonic acid, succinic acid, glutaric acid, adipic acid, suberic acid, azelaic acid, phthalic acid, and hexahydrophthalic acid (Hexahydrophthalicic acid). Selected from the group consisting of acid), aminosuccinic acid, and diphenic acid. Further, a representative example of a monobasic acid having a molecular weight of 150 or more and 300 or less may be phthalic acid, stearic acid, oleic acid, anisic acid, or benzoyl benzoate. Selected from the group consisting of benzoate), dichlorobenzoic acid, dibromodelic acid, diphenylacetic acid, and cuminic acid. Further, a representative example of the dibasic acid having a molecular weight of 300 or more and 600 or less may be an esterification reaction product of No. SL-20 (manufactured by Okamura Oil Co., Ltd.), diethylene glycol and anhydrous succinic acid, and (meth)acrylic acid of an unsaturated fatty acid. The adduct and the dimer of the unsaturated fatty acid are selected from the group consisting of. In addition, as an example of other applicable active agents, hydrogen halide hydrochloride, lactic acid, or citric acid such as ethylamine, propylamine, diethylamine, triethylamine, diphenylguanidine, ethylenediamine, aniline or the like can be used. .

The amount of the dibasic acid having a molecular weight of 250 or less, the monobasic acid having a molecular weight of 150 or more and 300 or less, and the dibasic acid having a molecular weight of 300 or more and 600 or less are not particularly limited. However, from the viewpoint of achieving weldability and reliability at the same time, the weight fraction of the monobasic acid having a molecular weight of 150 or more and 300 or less is 100 parts by weight or more and 500 parts by weight or less with respect to 100 parts by weight of the dibasic acid having a molecular weight of 250 or less. It is better. From the above viewpoints, it is more preferable that the dibasic acid having a molecular weight of 250 or less is 100 parts by weight or more, and particularly preferably a molecular weight of 150 or more and 300 or less. On the other hand, from the above viewpoints, the dibasic acid having a molecular weight of 300 or more and 600 or less is preferably from 80 or more to 400 or less by weight based on 100 parts by weight of the dibasic acid having a molecular weight of 250 or less. From the above viewpoints, the dibasic acid having a molecular weight of 300 or more and 600 or less is preferably more than 80 parts by weight to 300 parts by weight based on 100 parts by weight of the dibasic acid having a molecular weight of 250 or less.

Moreover, the amount of use of either or both of high-density polyethylene and polypropylene may be in the range of 4% by weight or more and 12% by weight or less (100% by weight of the entire flux). However, from the viewpoint of preventing the heating collapse and the ease of adjustment of the viscosity of the solder paste, the weight portion of either or both of the high-density polyethylene and the polypropylene is 5 or more with respect to 100 parts by weight of the flux. The weight of 9 or less is better.

Here, in the high-density polyethylene used in the present embodiment, the particle size, particle size distribution, or shape of the particulate high-density polyethylene in the flux for solder paste is at least in accordance with the following conditions (a) to (d). At least one of them.

(a) The average diameter of the longest diameter of the particle diameter of the high-density polyethylene is 0.001 μm or more and 50 μm or less.

(b) A high-density polyethylene having a longest diameter of 60 μm or less in a field of view of 1.5 mm × 1.1 mm which is randomly selected from the flux for solder paste when observed by an optical microscope at a magnification of 200 times. Counting more than 90% of the total number of high density polyethylene.

(c) When observed by an optical microscope at a magnification of 100 times, the high-density polyethylene having a longest diameter of 100 μm or more in the field of view of 3.1 mm × 2.3 mm which is randomly selected from the flux for solder paste is used. The number is less than 1% of the total number of the high-density polyethylene.

(d) The high density polyethylene is polyhedral.

By satisfying the above-mentioned conditions, for example, the accuracy of providing the high-density polyethylene in the flux on the electrode or the like after the refining can be improved, so that the applicability to the miniaturized electronic circuit parts and the like can be further improved. In addition, Fig. 1 is an optical micrograph of a flux constituting a part of the solder paste of the present embodiment. As shown in Fig. 1, for the flux, a high-density polyethylene having a complex particle diameter (controlled within the above range) was observed. In the case of the flux shown in Fig. 1, when the measurement was carried out by the particle size measuring device, it was not confirmed that there was a trace larger than 50 μm, so the longest diameter of the high-density polyethylene was about 50 μm or less. Also, most high density polyethylenes are polyhedral. Further, in each of the above conditions (a) to (d), it is preferable to satisfy two or more items at the same time, and it is more preferable to satisfy all the conditions.

On the other hand, a high-density polyethylene having a viscosity molecular weight of 1,500 or more and 4500 or less is a preferred embodiment. If the range of the viscosity molecular weight described above can be satisfied, the suppression of "collapse" during heating can be further enhanced.

Further, the melting point of the high-density polyethylene is preferably 110 ° C or more and 130 ° C or less. If the range of the above melting point can be satisfied, the suppression of "collapse" during heating can be further enhanced.

Further, the high-density polyethylene having an acid value of 1 or less is another preferred embodiment. If the range of the aforementioned acid value is satisfied, the reduction in insulation reliability due to the addition of high-density polyethylene can be prevented.

Further, the glass transition temperature of the high-density polyethylene is -50 ° C or less, which is another preferred state. If the range of the glass transition temperature can be satisfied, the deterioration of the crack resistance of the flux residue can be suppressed (this is especially required for the paste for the in-vehicle electronic parts).

In the polypropylene used in the present embodiment, the particle size, particle size distribution or shape of the particulate polypropylene in the solder paste flux is preferably at least in the following conditions (a) to (d). At least one of them.

(a) The average diameter of the longest diameter of the particle diameter of the polypropylene is 0.001 μm or more and 50 μm or less.

(b) When observed by an optical microscope at a magnification of 200 times, the number of polypropylene having a longest diameter of 60 μm or less in the field of view of 1.5 mm × 1.1 mm which is randomly selected from the flux for solder paste is up to More than 90% of the total amount of polypropylene.

(c) The number of polypropylenes having a maximum diameter of 100 μm or more in a field of view of 3.1 mm × 2.3 mm randomly selected from the flux for solder paste when observed by an optical microscope at a magnification of 100 times It is 1% or less of the total number of the polypropylene.

(d) The polypropylene is polyhedral.

When the above conditions are satisfied, for example, the accuracy of providing the polypropylene in the flux on the electrode or the like after the refining can be improved, so that the applicability to the miniaturized electronic circuit parts and the like can be further improved. Further, among the above conditions (a) to (d), it is preferable to satisfy two or more items at the same time, and it is more preferable to satisfy all the conditions.

Here, a polypropylene having a viscosity molecular weight of 5,000 or more and 20,000 or less is a preferred embodiment. If the viscosity molecular weight range is satisfied, the suppression of "collapse" during heating can be further improved.

Further, a polypropylene having a melting point of 130 ° C or more and 160 ° C or less is another preferred embodiment. If the range of the above melting point can be satisfied, the suppression of "collapse" during heating can be further improved.

Further, the acid value of polypropylene is preferably 1 or less. If the range of the aforementioned acid value is satisfied, the reduction in insulation reliability due to the addition of polypropylene can be prevented.

Further, the glass transition temperature of polypropylene is 0 ° C or less is another preferred state. If the range of the glass transition temperature can be satisfied, the deterioration of the crack resistance of the flux residue can be suppressed (this is especially required for the paste for the in-vehicle electronic parts).

Further, as described above, it is not limited to the solder paste of only one of the above-mentioned high-density polyethylene or the above-mentioned polypropylene, and the flux for solder paste containing the above two is also preferable. The solder paste having both high-density polyethylene and polypropylene can exhibit the above-described respective effects if it satisfies the above-described preferred ranges.

On the other hand, each of the above-mentioned solder pastes further contains a waxy product obtained by subjecting a higher aliphatic monocarboxylic acid, a polybasic acid, and a diamine to a dehydration reaction at a melting point of 100 ° C or higher. The waxy product promotes the action of the high density polyethylene or polypropylene.

By using the aforementioned solder paste, the activity of the dibasic acid having a molecular weight of 250 or less can be improved. Therefore, good weldability can be ensured. Further, a monobasic acid having a molecular weight of 150 or more and 300 or less and a dibasic acid having a molecular weight of 300 or more and 600 or less can be used to promote the activity. Further, the aforementioned monobasic acid and dibasic acid which are used together with a dibasic acid having a molecular weight of 250 or less can uniformly disperse a metal salt of a low molecular weight dibasic acid into a flux residue, and can be made of rosin or propylene. A hydrophobic base resin such as a resin is used to coat the metal salt. Here, the metal salt of the low molecular weight dibasic acid is a metal salt which is generated at the time of soldering and which is not easily dissolved in the flux residue. Therefore, not only the problem of decomposition and ionization of the organic acid metal salt in the residue due to moisture but also the ionization of the residual organic acid can be suppressed. As a result, a flux which can further suppress the occurrence of electrical insulation failure and corrosion can be obtained. Further, the solder paste containing the flux described above has good solderability and reliability.

In addition, from the viewpoint of improving the crack resistance of the residue, the resin included in the flux of the solder paste of the present embodiment can be a resin typified by a propylene-based resin excellent in flexibility. More preferably, however, any one or both of rosin and its derivatives used in the past have been further added. Further, in the case where either or both of rosin and its derivatives are used, the amount of the rosin and its derivative used or both is not particularly limited. However, the content of either or both of rosin and its derivative is 10 parts by weight or more and 50 parts by weight with respect to 100 parts by weight of the flux, from the viewpoints of welding performance, corrosion resistance, and printing workability. It is preferred to use the following parts by weight. Moreover, from the above viewpoint, the content of either or both of the rosin and the derivative thereof is more preferably 15 parts by weight or more and 30 parts by weight or less based on 100 parts by weight of the flux.

Further, a representative example of the aforementioned rosin is a usual gum rosin, tall oil rosin, or wood rosin. Further, representative examples of the derivative are heat-treated resin, polymerized rosin, hydrogenated rosin, formamyl rosin, rosin ester, rosin-denatured maleic acid resin, rosin-modified phenol resin, and acrylic acid-added rosin. Or rosin-denatured alkyd resin. These rosins and their derivatives are useful as binders for uniformly applying the active agent to the metal.

In addition, a representative example of the propylene-based resin is a thermoplastic propylene-based resin obtained by polymerizing a monomer having a polymerizable unsaturated group by radical polymerization. Here, representative examples of the monomer having a polymerizable unsaturated group are (meth)acrylic acid, various esters thereof, crotonic acid, itaconic acid, (anhydrous) maleic acid, and the like. Esters, (meth)acrylonitrile, (meth)acrylamide, polyvinyl chloride, vinyl acetate. Further, a typical radical polymerization method is a bulk polymerization method, a liquid polymerization method, a suspension polymerization method or an emulsion polymerization method using a peroxide or the like as a catalyst, but other conventional polymerization methods can also be applied. In addition, in order to obtain excellent crack resistance and flexibility, the propylene resin preferably has a weight average molecular weight of 6,000 or more and 12,000 or less, and more preferably has a number average molecular weight of 4,000 or more and 6,000 or less.

Further, a preferred example of the solvent used in the present embodiment is a polar solvent which can easily dissolve a component such as an active agent or a resin and can be used as a solution. An alcohol system is typically used, and in particular, diethylene glycol monoethers are excellent in solubility in volatiles and active agents. Further, in the case of using the above solvent, the amount of the solvent to be used is not particularly limited. However, from the viewpoint of the print workability or the stability of the solder paste, the solvent is preferably 15 parts by weight or more and 40 parts by weight or less based on 100 parts by weight of the flux. However, in the case where a plurality of solvents are used in combination, the total content of the solvents is preferably in the above range. Moreover, in view of the above, the solvent is preferably 20 parts by weight or more and 35 parts by weight or less.

Further, when the solder paste of the present embodiment is produced, a solvent can be used as needed. The type of the solvent is not particularly limited. However, in view of the fact that solder paste is not easily evaporated, it is preferred to use a solvent having a boiling point of 150 ° C or higher. Specific examples include triethylene glycol monomethyl ether, triethylene glycol dimethyl ether, tetraglyme dimethyl ether, diethylene glycol monomethyl ether, diethylene glycol monobutyl ether, diethylene glycol monohexyl ether, Ethylene glycol monophenyl ether, diethylene glycol monophenyl ether, diethylene glycol monobutyl acetate, dipropylene glycol, diethylene glycol-2-octyl ether, α-rosinol, benzyl alcohol, 2- Hexyl decyl alcohol, butyl benzoate, diethyl adipate, diethyl decanoate, Dodecane, tetradecene, dodecylbenzene, ethylene glycol, digan Alcohol, dipropylene glycol, triethylene glycol, hexanediol, 1,5-pentanediol, methyl carbitol, butyl carbitol, and the like. Preferably, an example of using triethylene glycol dimethyl ether, tetraglyme dimethyl ether, diethylene glycol monobutyl ether acetic acid or the like as a solvent is exemplified.

Next, a method of manufacturing the flux used in the solder paste of the present embodiment will be described.

First, the flux of the present embodiment can be obtained by dissolving or mixing the above components in a conventional manner. For example, first, the components are heated, dissolved, and/or mixed in one breath or sequentially, and then cooled. Then, physical impact force is applied by a mechanical pulverization treatment process or an impact deformation destruction treatment process or the like. In addition, the physical impact force may be applied to either or both of high density polyethylene and polypropylene before the dissolution process described above. The flux of the present embodiment can be obtained by mixing the components using the above method. Specifically, a conventional device such as a kneading device, a vacuum agitation device, a homodisperser, a tree-one motor, or a planetary mixer can be used as a device for mixing the above components. . Here, the mixing temperature of each of the above components is not particularly limited. However, it is preferred to dissolve the aforementioned components by heating to a lower temperature than the boiling point of the solvent used for mixing.

Next, a method of manufacturing the solder paste of the present embodiment will be described.

First, the composition of the solder powder used in the solder paste of the present embodiment is not particularly limited. Specifically, for an example, the solder powder may include: tin (Sn), copper (Cu), zinc (Zn), silver (Ag), antimony (Sb), lead (Pb), indium (In) One or more components selected from the group consisting of bismuth (Bi), nickel (Ni), aluminum (Al), gold (Au), and yttrium (Ge). Moreover, as another example, the solder powder may also include: a conventional tin/lead alloy, tin/silver alloy, tin/silver/copper alloy, tin/silver/bismuth/indium, tin/copper alloy, tin/ Copper/nickel, tin/zinc alloy, tin/zinc/bismuth alloy, tin/zinc/aluminum alloy, tin/zinc/bismuth/aluminum alloy, tin/zinc/bismuth/indium alloy, tin/bismuth alloy and tin/indium alloy One or more components selected from the group consisting of.

Further, it is preferable that the shape of the welding powder is a true spherical shape or a substantially spherical shape. Further, the flux of the solder powder may be mixed with the above flux if it has a normal size. In addition, for example, in the case of using a solder powder of a true ball, it is preferable to use a solder powder having a diameter of 5 μm or more and 60 μm or less from the viewpoint of achieving high precision of packaging of the fine electronic component. Further, the composition ratio of the composition constituting the welding powder is also not particularly limited. For example, Sn63/Pb37, Sn96.5/Ag3.5, Sn96/Ag3.5/Cu0.5, Sn96.6/Ag2.9/Cu0.5, Sn96.5/Ag3.0/Cu0.5 Sn42/Bi58, Sn99.3/Cu0.7, Sn91/Zn9, Sn89/Zn8/Bi3, etc. are examples of preferred solder powders. In addition, each of the above numerical values shows the weight ratio of each metal.

The solder paste of the present embodiment is obtained by mixing and mixing the flux with the solder powder by a conventional means. Specifically, a conventional device such as a vacuum agitation device, a kneading device, or a planetary mixer can be used as a device for mixing and mixing the above components. Here, the processing temperature and conditions at the time of kneading preparation are not particularly limited. However, it is preferable to carry out the treatment at 5 ° C or more and 50 ° C or less from the viewpoint of absorbing moisture from the external environment, oxidation of the weld metal particles, and deterioration of the temperature due to an increase in temperature. Further, the weight ratio between the flux and the solder powder is not particularly limited. However, from the viewpoint of the print workability or the stability of the solder paste, it is preferable that the solder powder has a weight ratio of 80 or more and 95 or less with respect to the weight ratio of 5 or more and 20 or less of the flux.

Further, the solder paste of the present embodiment can be further provided with an oxidation preventing agent, a matting agent, a coloring agent, an antifoaming agent, a dispersion stabilizer, and a chelating agent, as needed within the scope of the effects of the embodiment. One or a plurality of materials selected from the group consisting of agents and the like are appropriately formulated.

On the other hand, the viscosity molecular weight of the polyethylene or polypropylene in the present application is a viscosity molecular weight Mv measured by a viscosity method using a Ubbelohde modified viscometer. The measurement of the specific viscosity molecular weight is as follows.

First, Decalin was added to the measurement sample, and the mixture was dissolved at 140 ° C for 30 minutes. The sample solution after the dissolution by heating was subjected to a viscosity meter to measure the number of seconds under flow at 135 ± 0.2 ° C, whereby an intrinsic viscosity ([η]) was obtained. Then, regarding polyethylene and polypropylene, each of [η] was substituted into the following formula to calculate the viscosity molecular weight.

[Formula 1]

Viscosity molecular weight of polyethylene = 2.51 × 104 × 1.235 [η]

[Formula 2]

Viscosity molecular weight of polypropylene = 10 × 105 × 1.25 [η]

Hereinafter, the above embodiment will be more specifically described based on the embodiments.

[Examples 1, 2, and Comparative Example 1]

In the first, second, and comparative examples 1, the solder paste containing high-density polyethylene was produced by the manufacturing method disclosed in the above embodiment. Table 1 shows the compositions of the solder pastes of Examples 1, 2, and Comparative Example 1 and the composition ratios thereof. Here, the high-density polyethylene used in the solder pastes of the first, second, and comparative examples 1 has an average diameter of the longest diameter of about 35 μm, and the viscosity molecular weights of the resins are about 2,000. The acid value is 0 at 120 ° C, the glass transition temperature is -120 ° C, and the density is 970 kg / m ³ . 2 is a graph showing the particle size distribution of the high-density polyethylene used in the first and second embodiments and the comparative example 1.

Further, the physical properties of the propylene-based resin A contained in the solder pastes of Examples 1 to 6 and Comparative Examples 1 to 3 have a weight average molecular weight of about 9000, a number average molecular weight of 5,000, and an acid value thereof. It is 0 and its glass transition temperature is -60 °C. Further, the polymerized rosin A contained in the solder pastes of Examples 1 to 6 and Comparative Examples 1 to 3 had a softening point of 140 ° C and an acid value of 145. Further, the solder powders of Example 1 and Comparative Example 1 were 3.0% by weight of silver and 0.5% by weight of copper with respect to 91.5% by weight of tin. Further, the solder powder of the first embodiment has a particle size distribution of 25 μm or more and 38 μm or less. Further, the solder powders used in the second to sixth embodiments and the comparative examples 1 to 3 are the same as those in the first embodiment, and the description of the solder powder is omitted.

[Examples 3, 4]

The solder pastes of the third and fourth embodiments were also produced in the same manner as in the first embodiment. Table 1 shows the compositions of the solder pastes of Examples 3 and 4 and their composition ratios. In addition, the average diameter of the longest diameter of the high-density polyethylene used in the solder paste of the third embodiment is about 5 μm, and the average diameter of the longest diameter of the high-density polyethylene used in the solder paste of the fourth embodiment is about 45 μm. Further, the physical properties of the high-density polyethylene are the same as those in the first embodiment except for the average particle diameter of the longest diameter. Therefore, the repeated explanation is omitted.

[Example 5]

The solder paste of the fifth embodiment was also produced in the same manner as in the first embodiment. Table 1 shows the composition of the solder paste of the fifth embodiment and the composition ratio thereof. Further, the high-density polyethylene used in the solder paste of the fifth embodiment has a viscosity molecular weight of about 4,000, a melting point of 130 ° C, a glass transition temperature of -100 ° C, and a density of 980 kg / m ³ . Further, the physical properties of the high-density polyethylene are the same as those in the first embodiment except for the viscosity molecular weight, the melting point, the glass transition temperature, and the density. Therefore, the repeated explanation is omitted.

[Embodiment 6]

The solder paste of the sixth embodiment was also produced in the same manner as in the first embodiment. Table 1 shows the composition of the solder paste of the sixth embodiment and the composition ratio thereof. In addition, the solder paste of the sixth embodiment was added to the composition of the fifth embodiment, and a waxy product (trade name: Light Amide WH-255, manufactured by Kyoeisha Chemical Co., Ltd.) was added in an amount of 0.1% by weight. Further, the physical properties of the high-density polyethylene were the same as in the fifth embodiment. Therefore, the repeated explanation is omitted.

[Comparative Examples 2, 3]

The solder pastes of Comparative Examples 2 and 3 were also produced in the same manner as in Example 1. Table 1 shows the compositions of the solder pastes of Comparative Examples 2 and 3 and the composition ratio thereof. Further, the low-density polyethylene used in the solder paste of Comparative Example 2 has an average diameter of the longest diameter of about 40 μm, a viscosity molecular weight of about 2,500, a melting point of 105 ° C, an acid value of 0, and a glass transition temperature thereof. It is -110 °C. Further, the low-density polyethylene used in the solder paste of Comparative Example 3 has an average diameter of the longest diameter of about 38 μm, a viscosity molecular weight of about 4,500, a melting point of 105 ° C, an acid value of 0, and a glass transition temperature thereof. It is -100 °C. Further, Comparative Example 2 of low-density polyethylene A, Comparative Example 3 and a low density polyethylene of density B are both 920kg / m ^3.

[Examples 7, 8 and Comparative Examples 4 to 6]

In the seventh and eighth embodiments, the solder paste containing the polypropylene A was produced by the manufacturing method disclosed in the above embodiment. Table 2 shows the compositions of the solder pastes of Examples 7 and 8 and the composition ratios thereof. Further, as a comparative example, Table 2 also shows the compositions of Comparative Examples 4 to 6 and the composition ratios thereof. The solder pastes of Comparative Examples 4 to 6 were also produced by the manufacturing method disclosed in the above embodiments. Here, the average diameter of the longest diameter of the polypropylene A used in the solder pastes of the seventh and eighth embodiments is about 30 μm, the viscosity molecular weights are about 10,000, and the melting points are 145 ° C. With a value of 0, the glass transition temperatures are about -20 °C. Further, in the solder paste of Comparative Example 4, a hardened castor oil was mixed instead of the polypropylenes A and B. Further, in the solder paste of Comparative Example 5, a medium density polyethylene A was mixed in place of the polypropylenes A and B, and the average diameter of the longest diameter was about 33 μm, the molecular weight of the viscosity was about 2,700, and the melting point thereof was 110 ° C. The acid value was 30, the glass transition temperature was about -80 ° C, and the density was 930 kg / m ³ . Further, the solder paste of Comparative Example 6 contained 0.9% by weight of hexamethylenebis 12 hydroxystearic acid amide without containing polypropylene A and B.

Further, the physical properties of the propylene-based resin B contained in the solder pastes of Examples 7 to 13 and Comparative Examples 4 to 6 have a weight average molecular weight of about 9000 and a number average molecular weight of 5,000. The value is 3 and the glass transition temperature is -55 °C. Further, the hydrogenated rosin contained in the solder pastes of Examples 7 to 13 had a softening point of 81 ° C and an acid value of 165. Further, the solder powder of the seventh embodiment was the same as the solder powder of the first embodiment. Further, the eighth embodiment to the thirteenth embodiment and the comparative example 4 to the comparative example 6 are also the same as those of the eleventh embodiment, and therefore the description of the solder powder is omitted.

[Examples 9, 10]

The solder pastes of the embodiments 9 and 10 were also produced in the same manner as in the seventh embodiment. Table 2 shows the composition of the solder pastes of the present Examples 9 and 10 and the composition ratio thereof. Further, the average diameter of the longest diameter of the polypropylene A used in the solder paste of the ninth embodiment was about 8 μm, and the average diameter of the longest diameter of the polypropylene A used in the solder paste of the tenth embodiment was about 42 μm. Further, the physical property values of polypropylene were the same as those of Example 7 except for the average particle diameter of the longest diameter. Therefore, the repeated explanation is omitted.

[Example 11]

The solder paste of this Example 11 was also produced in the same manner as in Example 7. Table 2 shows the composition of the solder paste of the present embodiment 11 and the composition ratio thereof. Further, the polypropylene B used in the solder paste of the present embodiment has an average diameter of a longest diameter of about 20 μm, a viscosity molecular weight of about 19,000, a melting point of 147 ° C, an acid value of 0, and a glass transition temperature of -25 ° C.

[Embodiment 12]

The solder paste of this Example 12 was also produced in the same manner as in Example 7. Table 2 shows the composition of the solder paste of the present embodiment 12 and the composition ratio thereof. Further, the solder paste of the present Example 12 contained a 0.1% by weight waxy product (trade name: Light Amide WH-255, manufactured by Kyoeisha Chemical Co., Ltd.) in addition to the composition of Example 11. Further, the physical properties of the polypropylene B were the same as in the eleventh embodiment. Therefore, the repeated explanation is omitted.

[Example 13]

The solder paste of this Example 13 was also produced in the same manner as in Example 7. Table 2 shows the composition of the solder paste of this Example 13 and its composition ratio. Further, the solder paste of the present Example 13 contained 0.4% by weight of each of the high-density polyethylene A used in Example 1 and the polypropylene A used in Example 7.

The results of analysis of the solder pastes of the above-described Embodiments 1 to 13 and the solder pastes of Comparative Examples 1 to 6 are as shown in Table 3. It has been confirmed that the solder pastes of Examples 1 to 13 have Helps improve heat and collapse resistance. Further, the solder pastes of Examples 1 to 13 had a viscosity at 80 ° C of 400 Pa ‧ or more. Since the solder paste was heated at a high viscosity, good results were obtained in the heating collapse test using the solder paste after 4 hours of continuous printing. Further, the insulation resistance values of the solder pastes of the above-described Embodiments 1 to 13 can be maintained at a relatively high value. In addition, in Table 3, the unit of "heating collapse" is mm, and the unit of "insulation resistance" value is Ω.

On the other hand, in Comparative Example 1, Comparative Example 4, and Comparative Example 6, the viscosity of the solder paste at 80 ° C was 400 Pa ‧ or less, and it was confirmed that the heating collapse characteristics were inferior to those of the above respective examples. Further, in Comparative Example 2, Comparative Example 3, and Comparative Example 5, the viscosity of the solder paste at 80 ° C was 400 Pa ‧ or more, but the insulation properties were confirmed as compared with the insulating properties of the above respective examples. Poor.

Further, the measurement of the viscosity of the solder paste in the present application was carried out by using a viscoelasticity measuring device. The details are as follows.

(1) The solder paste as a sample was sandwiched between a sample stage of the measuring device and a stainless steel parallel plate having a diameter of 25 mm of the measuring jig.

(2) The gap between the sample stage and the parallel plate is 1.0 mm.

(3) Stress was applied under the conditions of a frequency of 5 Hz and an oscillation angle of 0.1%, and the viscosity was measured at 80 °C.

The foregoing embodiments and examples are not intended to limit the invention. Modifications included in the scope of the present invention, including the above-described embodiments and other combinations of the respective embodiments, are also included in the scope of the present application.

The solder paste of the present invention is extremely useful for soldering systems for various applications such as electronic circuit parts.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is an optical micrograph of a flux in an embodiment of the present invention.

Fig. 2 is a graph showing the particle size distribution of the high density polyethylene of Example 1 of the present invention.

Claims (13)

A solder paste comprising at least one resin additive selected from the group consisting of high-density polyethylene and polypropylene in a flux, and when the flux is 100% by weight as a whole, The resin additive is 4% by weight or more and 12% by weight or less, and has a viscosity at 80 ° C of 400 Pa ‧ s or more, wherein the active agent has a dibasic acid having a molecular weight of 250 or less, and a monobasic acid having a molecular weight of 150 or more and 300 or less And a dibasic acid having a molecular weight of 300 or more and 600 or less; and the dibasic acid having a molecular weight of 250 or less is composed of malonic acid, succinic acid, glutaric acid, adipic acid, suberic acid, sebacic acid, and benzene. The group consisting of acid, hexahydrophthalic acid, amino succinic acid, and diphenyl phthalic acid; the monobasic acid having a molecular weight of 150 or more and 300 or less is made of citric acid, stearic acid, or oleic acid. Selected from the group consisting of anisic acid, benzyl benzoate, dichlorobenzoic acid, dibromodelic acid, diphenylacetic acid, and petroselinic acid; the binary having a molecular weight of 300 or more and 600 or less Acidic esterification reaction of diethylene glycol with anhydrous succinic acid, unsaturated fat The group consisting of (meth) acrylic acid adduct, and a dimer of an unsaturated fatty acid selected. The solder paste of claim 1, wherein the high-density polyethylene in the form of particles in the flux for soldering meets at least one of the following conditions (a) to (d), namely: (a) The average diameter of the longest diameter of the particle diameter of the high-density polyethylene is 0.001 μm or more and 50 μm or less; (b) When observed by an optical microscope at a magnification of 200 times, it is randomly used in the flux for solder paste described above. In the selected 1.5 mm × 1.1 mm field of view, the number of the high-density polyethylene having a longest diameter of 60 μm or less is more than 90% of the total number of the high-density polyethylene; (c) by an optical microscope at a magnification of 100 When the observation is repeated, the number of the high-density polyethylene having a maximum diameter of 100 μm or more in the field of view of 3.1 mm × 2.3 mm which is randomly selected from the flux for solder paste is the total number of the high-density polyethylene. Less than 1%; or (d) the high density polyethylene is polyhedral. The solder paste of claim 1 or 2, wherein the high density polyethylene has a viscosity molecular weight of 1,500 or more and 4500 or less. The solder paste of claim 1 or 2, wherein the high-density polyethylene has a melting point of 110 ° C or more and 130 ° C or less. The solder paste of claim 1 or 2, wherein the high density polyethylene has an acid value of 1 or less. The solder paste of claim 1 or 2, wherein the high density polyethylene has a glass transition temperature of -50 ° C or less. The solder paste according to claim 1, wherein the polypropylene in the flux for solder paste meets at least one of the following conditions (a) to (d), that is, (a) the poly The average diameter of the longest diameter of the particle size of propylene is 0.001 μm or more and 50 μm or less; (b) When observed by an optical microscope at a magnification of 200 times, the longest diameter of the particle diameter is 60 μm or less in the field of view of 1.5 mm × 1.1 mm randomly selected from the flux for solder paste. The number of the polypropylene is more than 90% of the total number of the polypropylene; (c) the 3.1 mm × 2.3 mm field of view randomly selected from the flux for solder paste when observed by an optical microscope at a magnification of 100 times In the range, the number of the polypropylene having a longest diameter of 100 μm or more is 1% or less of the total number of the polypropylene; or (d) the polypropylene is polyhedral. The solder paste of claim 1 or 7, wherein the polypropylene has a viscosity molecular weight of 5,000 or more and 20,000 or less. The solder paste of claim 1 or 7, wherein the polypropylene has a melting point of 130 ° C or more and 160 ° C or less. The solder paste of claim 1 or 7, wherein the polypropylene has an acid value of 1 or less. The solder paste of claim 1 or 7, wherein the polypropylene has a glass transition temperature of 0 ° C or less. The solder paste of claim 1 or 2 or 7 further comprising a waxy product which dehydrates a system containing a higher aliphatic monocarboxylic acid, a polybasic acid, and a diamine. The winner. The solder paste of claim 12, wherein the waxy product has a melting point of 100 ° C or more.